Things is one of those apps you've probably heard a ton about, but looked away as soon as you saw the $50 price tag. If you're a fan of the GTD productivity system—or a variant of it—a lot of people swear by things. It's very polished and well-done, and while it may not be worth $50 to you, $25 might be a more doable price. You can try out a free trial on their site before purchasing too, so give it a shot—just make sure you buy it before the deal ends on January 31st.